NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
Resist removed by ashing - a plasma process which “burns” the resist off the surface
(Note - Resist contains measurable amounts of impurities such as sodium.)
Ashing concentrates impurities on the surface.
Must be followed by a wet process to remove contaminants
Sulfuric acid-hydrogen peroxide used before metal is present on the wafer
Solvent strippers used after metal deposition